Any maintenance district created to finance any work which might also be constructed or maintained by a county sanitation district, may become a part of a county sanitation district after the board of supervisors of the county within which the maintenance district is located has, after a hearing held pursuant to the County Sanitation District Act (Chapter 3 (commencing with Section 4700), Part 3, Division 5 of the Health and Safety Code), determined by resolution that such inclusion is for the best interest of the maintenance district and the governing body of the maintenance district consents to the inclusion by resolution adopted by the affirmative vote of a majority of its members.